A two-and-a-half-year study of England’s Lake Windermere has found that most of the country’s largest lake fails to meet safe bathing-water standards because of high concentrations of sewage-borne bacteria. The Big Windermere Survey, led by the Freshwater Biological Association and Lancaster University, analysed more than 1,000 samples collected by 350 volunteers and detected elevated levels of Escherichia coli and intestinal enterococci, particularly during the summer tourist season. Researchers also reported excessive phosphorus, indicating wider ecological stress. They linked the contamination to legal and illegal sewage discharges, agricultural runoff and poorly maintained private septic tanks. United Utilities, which operates wastewater facilities around the lake, said it is accelerating projects to reduce storm-overflow releases and further cut phosphorus after halving its own contributions in recent years. Environment Secretary Steve Reed has pledged to “clean up Windermere,” but the findings add pressure on the government to translate that promise into concrete enforcement and investment. The lake’s deterioration underscores a nationwide problem: only 14% of England’s rivers and lakes currently achieve good ecological status under existing water-quality regulations.